We will apply in vivo isotopic tracer methods to address the following specific aims: Aim 1: Quantify urea N recycling in cancer patients withand without cachexia and in normal healthy subjects, and evaluate the regulation of this process by a glucose infusion. Aim 2: Quantify the incorporate of orally administered N ammonia into a multiple non-essential and branched chain plasma amino acids and urea in the three experimental groups with and without a glucose infusion.